Tumbler plate lock

ABSTRACT

A lock wherein a flat key acts on tumbler plates, slidable in a core, to slide these several plates in one direction while an elastic biasing element or return spring, surrounding the structure, urges them in the opposite direction. The elastic element can directly contact a small boss on each tumbler plate. It urges each tumbler plate to return in the direction of the plate&#39;&#39;s axis, thereby minimizing looseness of the core and tumbler structure.

United States Patent [191 Lipschutz 11 3,777,521 1 Dec. 11, 1973 TUMBLERPLATE LOCK [75] Inventor: Paul Lipschutz, Croissy-sur-Siene,

France [73] Assignee: Societe dExploitation des Brevets NEIMAN,Neuilly-sur-Seine, France [22] Filed: June 14, 1972 [21] Appl. No.:262,878

[30] Foreign Application Priority Data June 17, 1971 France 7122041 [52]US. Cl. 70/364 R, 70/377 [51] Int. Cl E05b 15/14, E05b 29/00 [58] Fieldof Search 70/364 R, 377, 37 C,

70/DIG. 52, DIG. 53, DIG. 54', DIG. 55

[56] References Cited UNITED STATES PATENTS 2,829,513 4/1958 Fresard70/364 R 1,498,035 6/1924 Heyer 70/364 R FOREIGN PATENTS OR APPLICATIONS248,740 2/1948 Switzerland"... 70/364 R Primary Examiner-Robert L. WolfeAttorney-Albert C. Nolte, Jr. et a1.

[57] ABSTRACT A lock wherein a flat key acts on tumbler plates, slidable in a core, to slide these several plates in one direction while anelastic biasing element or return spring, surrounding the structure,urges them in the opposite direction. The elastic element can directlycontact a small boss on each tumbler plate. It urges each tumbler plateto return in the direction of the plates axis, thereby minimizinglooseness of the core and tumbler structure.

4 Claims, 6 Drawing Figures 1 TUMBLER PLATE LOCK BACKGROUND AND NATUREOF THE INVENTION:

Tumbler plate locks have encountered difficulty in connection withcorrect guidance of the tumbler plates. Conventionally these plates havereturn springs. Because of the geometry of the lock these have beenplaced on the sides of the tumblers and have therefore produced aneccentric push which tended to rock the tumbler plate in the slide spaceprovided for it, where some clearance always exists particularly after alarge number of lock operations.

The conventional construction also had the effect that a lateralabutment was necessary for the return spring, on the tumbler plate,thereby reducing the length of its stroke, across the core of the lock.

These shortcomings are overcome by the present invention, which for thispurpose replaces the lateral return spring by an elastic ring element,disposed about other parts of the core and which advantageously bears ona small boss or other projection or heel on each tumbler plate. Thisarrangement automatically centers the action of the new return springand thereby urges the tumbler plate to return along its axis. At thesame time the stroke of this plate can be made much longer than before.

DRAWINGS FIG. 1 (prior art) is a cross section through the core of aconvention lock;

FIG. 2 is a generally similar section taken along lines 2--2 in FIG. 3,through a lock constructed according to the invention;

FIG. 3 is a side view of the lock of FIG. 2;

FIG. 4 is a detail from FIG. 2, showing a tumbler plate in shiftedpotions;

FIG. 5 is a perspective view of a tumbler for the lock of FIG. 2; and

FIG. 6 is a perspective view of a modified lock according to theinvention.

As is shown in FIG. 1 with some exaggeration tumbler plate 1 is disposedin a diametric recess 1a of core 1b. A key hole 1c is provided in acentral region of the plate. The key (not shown) acts on a lower surface1d in the keyhole, whereby it urges plate 1 downwards,

subject to restraint by a side pin 2 on one side and a returncompression spring 3 on the other side of the plate between side walls 5and 6 of the slideway for thisplate. The position of the tumbler platein its recess is somewhat unpredictable, and can be inclined in variousdirections as the key is inserted and then turned. After some number oflock operations the plate may tend to be inclinded to almost the largeextent shown in this figure. This can make it difficult to insert thekey.

The lock of the invention shown in FIGS. 2 to 5 greatly reduces thisdifficulty even if the materials for the tumbler plate and core are thesame as in the earlier constructions. Each new tumbler plate 1' has alateral boss or heel 8, shown as a small tongue stuck out at from thestock of the plate, and elastic rings 4, surrounding suitable portionsof the core, push inwardly against the outsides of bosses 8, on thetumbler plates, whereby these plates are urged into theirnormalpositions, not displaced by key or spring action.

Desirably each boss is located substantially at, or at least close to,the central axis A of key hole 10. As best shown in FIGS. 4 and 5, theboss is slightly displaced from this axis, whereby a slight lateralpush, caused for example by rotary motion, can be compensated.

Elastic rings 4 can be replaced by a single, elastic spiral 12, as shownin FIG. 6.

In both cases, FIGS. 3 and 6, tumbler plate 1' can have straight,uninterrupted sidewalls 9, l0, sliding along side walls 5', 6' of thetumbler recess in the core. Wear and tear between walls 9, 5' and 10, 6'is less likely and less concentrated than in FIG. 1, and when some of itoccurs nevertheless it is less likely to cause tilting of plate 1 allthis by virture of the new, centrally acting return spring 4 or 6.

What is claimed is:

1. Lock for a flat key, comprising a core, tumbler plates therein, andspring means for returning the tumbler plates after displacement by thekey, the spring means being of annular form, surrounding the tumblerplates and bearing on substantially central parts of ends of saidplates, each plate having a boss, laterally extending from one of thesubstantially central parts, to be engaged by the spring means.

2. Lock according to claim 1 wherein each boss comprises a small heelstruck out of the plate.

3. Lock according to claim 1 wherein the spring means comprises aplurality of elastic rings.

4. Lock according to claim 1 wherein the spring means comprises anelastic helix.

1. Lock for a flat key, comprising a core, tumbler plates therein, andspring means for returning the tumbler plates after displacement by thekey, the spring means being of annular form, surrounding the tumblerplates and bearing on substantially central parts of ends of saidplates, each plate having a boss, laterally extending from one of thesubstantially central parts, to be engaged by the spring means.
 2. Lockaccording to claim 1 wherein each boss comprises a small heel struck outof the plate.
 3. Lock according to claim 1 wherein the spring meanscomprises a plurality of elastic rings.
 4. Lock according to claim 1wherein the spring means comprises an elastic helix.